Serving Text Classification Using Keras on AI Platform

Overview

This notebook illustrates the new feature of serving custom model prediction code on AI Platform. It allows us to execute arbitrary python pre-processing code prior to invoking a model, as well as post-processing on the produced predictions.

This is all done server-side so that the client can pass data directly to AI Platform Serving in the unprocessed state.

We will take advantage of this for text classification because it involves pre-processing that is not easily accomplished using native TensorFlow. Instead we will execute the the non TensorFlow pre-processing via python code on the server side.

We implement our Text Classifier using Keras. Keras is a high-level API for building and training deep learning models. tf.keras is TensorFlow’s implementation of this API. To learn more about building machine learning models in Keras more generally, read TensorFlow's Keras tutorials.

Dataset

Hacker News is one of many public datasets available in BigQuery. This dataset includes titles of articles from several data sources. For the following tutorial, we extracted the titles that belong to either GitHub, The New York Times, or TechCrunch, and saved them as CSV files in a publicly shared Cloud Storage bucket at the following location: gs://cloud-training-demos/blogs/CMLE_custom_prediction

Objective

The goal of this tutorial is to:

  1. Process the data for text classification.
  2. Train a Keras Text Classifier (locally).
  3. Deploy the Keras Text Classifier, along with the preprocessing artifacts, to AI Platform Serving, using the Custom Online Prediction code.

This tutorial focuses more on using this model with AI Platform Serving than on the design of the text classification model itself. For more details about text classification, please refer to Google developer's Guide to Text Classification.

Costs

This tutorial uses billable components of Google Cloud Platform (GCP):

  1. AI Platform Serving (Cloud Machine Learning Engine)
  2. Cloud Storage Learn about AI Platform Serving pricing and Cloud Storage pricing, and use the Pricing Calculator to generate a cost estimate based on your projected usage.

If you are using AI Platform Notebooks, your environment is already authenticated. Skip this step.


In [1]:
try:
 from google.colab import auth
 auth.authenticate_user()
except:
 pass

Setup


In [ ]:
%load_ext autoreload
%autoreload 2

In [ ]:
!pip install tensorflow==1.13.1

In [ ]:
import tensorflow as tf
print(tf.__version__)

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import os

PROJECT='' # SET TO YOUR GCP PROJECT NAME
BUCKET='' # SET TO YOUR GCS BUCKET NAME
ROOT='keras_text_classification'
MODEL_DIR=os.path.join(ROOT,'models')
PACKAGES_DIR=os.path.join(ROOT,'packages')

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!gcloud config set project {PROJECT}

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# Delete any previous artefacts from Google Cloud Storage
!gsutil rm -r gs://{BUCKET}/{ROOT}

Download and Explore Data


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# Download from Google Cloud Storage
%%bash
gsutil cp gs://cloud-training-demos/blogs/CMLE_custom_prediction/keras_text_pre_processing/train.tsv .
gsutil cp gs://cloud-training-demos/blogs/CMLE_custom_prediction/keras_text_pre_processing/eval.tsv .

In [ ]:
!head eval.tsv

Preprocessing

Pre-processing class to be used in both training and serving


In [ ]:
%%writefile preprocess.py

from tensorflow.python.keras.preprocessing import sequence
from tensorflow.keras.preprocessing import text

class TextPreprocessor(object):
  def __init__(self, vocab_size, max_sequence_length):
    self._vocab_size = vocab_size
    self._max_sequence_length = max_sequence_length
    self._tokenizer = None

  def fit(self, text_list):        
    # Create vocabulary from input corpus.
    tokenizer = text.Tokenizer(num_words=self._vocab_size)
    tokenizer.fit_on_texts(text_list)
    self._tokenizer = tokenizer

  def transform(self, text_list):        
    # Transform text to sequence of integers
    text_sequence = self._tokenizer.texts_to_sequences(text_list)

    # Fix sequence length to max value. Sequences shorter than the length are
    # padded in the beginning and sequences longer are truncated
    # at the beginning.
    padded_text_sequence = sequence.pad_sequences(
      text_sequence, maxlen=self._max_sequence_length)
    return padded_text_sequence

Test Prepocessing Locally


In [ ]:
from preprocess import TextPreprocessor

processor = TextPreprocessor(5, 5)
processor.fit(['hello machine learning'])
processor.transform(['hello machine learning'])

Model Creation

Metadata


In [ ]:
CLASSES = {'github': 0, 'nytimes': 1, 'techcrunch': 2}  # label-to-int mapping
VOCAB_SIZE = 20000  # Limit on the number vocabulary size used for tokenization
MAX_SEQUENCE_LENGTH = 50  # Sentences will be truncated/padded to this length

Prepare data for training and evaluation


In [ ]:
import pandas as pd
import numpy as np
from preprocess import TextPreprocessor

def load_data(train_data_path, eval_data_path):
    # Parse CSV using pandas
    column_names = ('label', 'text')
    df_train = pd.read_csv(
      train_data_path, names=column_names, sep='\t').sample(frac=1)
    df_eval = pd.read_csv(
      eval_data_path, names=column_names, sep='\t')

    return ((list(df_train['text']), np.array(df_train['label'].map(CLASSES))),
            (list(df_eval['text']), np.array(df_eval['label'].map(CLASSES))))


((train_texts, train_labels), (eval_texts, eval_labels)) = load_data(
       'train.tsv', 'eval.tsv')

# Create vocabulary from training corpus.
processor = TextPreprocessor(VOCAB_SIZE, MAX_SEQUENCE_LENGTH)
processor.fit(train_texts)

# Preprocess the data
train_texts_vectorized = processor.transform(train_texts)
eval_texts_vectorized = processor.transform(eval_texts)

Save pre-processing object

We need to save this so the same tokenizer used at training can be used to pre-process during serving


In [ ]:
import pickle

with open('./processor_state.pkl', 'wb') as f:
  pickle.dump(processor, f)

Build the model


In [ ]:
import tensorflow as tf

from tensorflow.keras import models
from tensorflow.keras.layers import Dense
from tensorflow.keras.layers import Dropout
from tensorflow.keras.layers import Embedding
from tensorflow.keras.layers import Conv1D
from tensorflow.keras.layers import MaxPooling1D
from tensorflow.keras.layers import GlobalAveragePooling1D


tf.logging.set_verbosity(tf.logging.INFO)

#keras model

def create_model(vocab_size, embedding_dim, 
  filters, kernel_size, dropout_rate, pool_size):
  
  model = models.Sequential()
  model.add(Embedding(input_dim=vocab_size,
                          output_dim=embedding_dim,
                          input_length=MAX_SEQUENCE_LENGTH))

  model.add(Dropout(rate=dropout_rate))
  model.add(Conv1D(filters=filters,
                            kernel_size=kernel_size,
                            activation='relu',
                            bias_initializer='random_uniform',
                            padding='same'))

  model.add(MaxPooling1D(pool_size=pool_size))
  model.add(Conv1D(filters=filters * 2,
                            kernel_size=kernel_size,
                            activation='relu',
                            bias_initializer='random_uniform',
                            padding='same'))
  model.add(GlobalAveragePooling1D())
  model.add(Dropout(rate=dropout_rate))
  model.add(Dense(len(CLASSES), activation='softmax'))

  return model

Train and save the model


In [ ]:
LEARNING_RATE=.001
EMBEDDING_DIM=200
FILTERS=64
KERNEL_SIZE=3
DROPOUT_RATE=0.2
POOL_SIZE=3

NUM_EPOCH=1
BATCH_SIZE=128

model = create_model(VOCAB_SIZE, EMBEDDING_DIM, 
  FILTERS, KERNEL_SIZE, DROPOUT_RATE,POOL_SIZE)

# Compile model with learning parameters.
optimizer = tf.keras.optimizers.Adam(lr=LEARNING_RATE)
model.compile(
  optimizer=optimizer, loss='sparse_categorical_crossentropy', metrics=['acc'])

#keras train
model.fit(
  train_texts_vectorized, train_labels, epochs=NUM_EPOCH, batch_size=BATCH_SIZE)
print('Eval loss/accuracy:{}'.format(
  model.evaluate(eval_texts_vectorized, eval_labels, batch_size=BATCH_SIZE)))

#save model
model.save('keras_saved_model.h5')

Custom Model Prediction Preparation

Copy model and pre-processing object to GCS


In [ ]:
!gsutil cp keras_saved_model.h5 gs://{BUCKET}/{MODEL_DIR}/
!gsutil cp processor_state.pkl gs://{BUCKET}/{MODEL_DIR}/

Define Model Class


In [ ]:
%%writefile model_prediction.py

import os
import pickle
import numpy as np


class CustomModelPrediction(object):

  def __init__(self, model, processor):
    self._model = model
    self._processor = processor

  def _postprocess(self, predictions):
    labels = ['github', 'nytimes', 'techcrunch']
    label_indexes = [np.argmax(prediction) for prediction in predictions]
    return [labels[label_index] for label_index in label_indexes]


  def predict(self, instances, **kwargs):
    preprocessed_data = self._processor.transform(instances)
    predictions =  self._model.predict(preprocessed_data)
    labels = self._postprocess(predictions)
    return labels


  @classmethod
  def from_path(cls, model_dir):
    import tensorflow.keras as keras
    model = keras.models.load_model(
      os.path.join(model_dir,'keras_saved_model.h5'))
    with open(os.path.join(model_dir, 'processor_state.pkl'), 'rb') as f:
      processor = pickle.load(f)

    return cls(model, processor)

Test Model Class Locally


In [ ]:
# Headlines for Predictions

techcrunch=[
  'Uber shuts down self-driving trucks unit',
  'Grover raises €37M Series A to offer latest tech products as a subscription',
  'Tech companies can now bid on the Pentagon’s $10B cloud contract'
]
nytimes=[
  '‘Lopping,’ ‘Tips’ and the ‘Z-List’: Bias Lawsuit Explores Harvard’s Admissions',
  'A $3B Plan to Turn Hoover Dam into a Giant Battery',
  'A MeToo Reckoning in China’s Workplace Amid Wave of Accusations'
]
github=[
  'Show HN: Moon – 3kb JavaScript UI compiler',
  'Show HN: Hello, a CLI tool for managing social media',
  'Firefox Nightly added support for time-travel debugging'
]
requests = (techcrunch+nytimes+github)

In [ ]:
from model_prediction import CustomModelPrediction

classifier = CustomModelPrediction.from_path('.')
results = classifier.predict(requests)
results

Package up files and copy to GCS


In [ ]:
%%writefile setup.py

from setuptools import setup

setup(
  name="my_package",
  version="0.1",
  include_package_data=True,
  scripts=["preprocess.py", "model_prediction.py"]
)

In [ ]:
!python setup.py sdist
!gsutil cp ./dist/my_package-0.1.tar.gz gs://{BUCKET}/{PACKAGES_DIR}/my_package-0.1.tar.gz

Model Deployment to CMLE


In [ ]:
MODEL_NAME='keras_text_classification'
VERSION_NAME='v201903'
RUNTIME_VERSION='1.13'
REGION='us-central1'

In [ ]:
!gcloud ai-platform models create {MODEL_NAME} --regions {REGION}

In [ ]:
!gcloud ai-platform versions delete {VERSION_NAME} --model {MODEL_NAME} --quiet # run if version already created

In [ ]:
!gcloud beta ai-platform versions create {VERSION_NAME} --model {MODEL_NAME} \
--origin=gs://{BUCKET}/{MODEL_DIR}/ \
--python-version=3.5 \
--runtime-version={RUNTIME_VERSION} \
--framework='SCIKIT_LEARN' \
--package-uris=gs://{BUCKET}/{PACKAGES_DIR}/my_package-0.1.tar.gz \
--prediction-class=model_prediction.CustomModelPrediction

Online Predictions from CMLE


In [ ]:
from googleapiclient import discovery
from oauth2client.client import GoogleCredentials
import json

# JSON format the requests
request_data = {'instances': requests}

# Authenticate and call CMLE prediction API 
credentials = GoogleCredentials.get_application_default()
api = discovery.build(
  'ml', 'v1', credentials=credentials,
  discoveryServiceUrl='https://storage.googleapis.com/cloud-ml/discovery/ml_v1_discovery.json')

parent = 'projects/{}/models/{}/versions/{}'.format(PROJECT, MODEL_NAME, VERSION_NAME)
print("Model full name: {}".format(parent))
response = api.projects().predict(body=request_data, name=parent).execute()

print(response['predictions'])

License

Authors: Khalid Salama & Vijay Reddy


Disclaimer: This is not an official Google product. The sample code provided for an educational purpose.


Copyright 2019 Google LLC

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.